Multilayer factors associated with excess all-cause mortality during the omicron and non-omicron waves of the COVID-19 pandemic: time series analysis in 29 countries.

BACKGROUND: The COVID-19 pandemic has resulted in significant excess mortality globally. However, the differences in excess mortality between the Omicron and non-Omicron waves, as well as the contribution of local epidemiological characteristics, population immunity, and social factors to excess mortality, remain poorly understood. This study aims to solve the above problems. METHODS: Weekly all-cause death data and covariates from 29 countries for the period 2015-2022 were collected and used. The Bayesian Structured Time Series Model predicted expected weekly deaths, stratified by gender and age groups for the period 2020-2022. The quantile-based g-computation approach accounted for the effects of factors on the excess all-cause mortality rate. Sensitivity analyses were conducted using alternative Omicron proportion thresholds. RESULTS: From the first week of 2021 to the 30th week of 2022, the estimated cumulative number of excess deaths due to COVID-19 globally was nearly 1.39 million. The estimated weekly excess all-cause mortality rate in the 29 countries was approximately 2.17 per 100,000 (95% CI: 1.47 to 2.86). Weekly all-cause excess mortality rates were significantly higher in both male and female groups and all age groups during the non-Omicron wave, except for those younger than 15 years (P < 0.001). Sensitivity analysis confirmed the stability of the results. Positive associations with all-cause excess mortality were found for the constituent ratio of non-Omicron in all variants, new cases per million, positive rate, cardiovascular death rate, people fully vaccinated per hundred, extreme poverty, hospital patients per million humans, people vaccinated per hundred, and stringency index. Conversely, other factors demonstrated negative associations with all-cause excess mortality from the first week of 2021 to the 30th week of 2022. CONCLUSION: Our findings indicate that the COVID-19 Omicron wave was associated with lower excess mortality compared to the non-Omicron wave. This study's analysis of the factors influencing excess deaths suggests that effective strategies to mitigate all-cause mortality include improving economic conditions, promoting widespread vaccination, and enhancing overall population health. Implementing these measures could significantly reduce the burden of COVID-19, facilitate coexistence with the virus, and potentially contribute to its elimination.

Assessing the influencing factors of out-of-pocket costs on tuberculosis in Sichuan Province: a cross-sectional study.

BACKGROUND: Although diagnosis and treatment services for tuberculosis (TB) are provided free of charge in most countries, direct non-medical and indirect costs due to absenteeism, also place a significant burden on patients and their families. Sichuan Province has the second highest incidence of TB in China, with an incidence of approximately 100 cases per 100 000 people. However, there are limited research on out-of-pocket expenditure (OOPE) and its influencing factors in TB patients in Sichuan Province. METHODS: A retrospective cross-sectional study was conducted on TB patients in designated medical institutions for TB in Sichuan Province from 2017-2021. A face-to-face questionnaire was conducted to obtain the information related to hospitalization of patients, and the multi-level regression model was used to analyse the factors that influence OOPE and total out-of-pocket expenditure (TOOPE) of TB patients. RESULTS: A total of 2644 patients were investigated, and 74.24% of TB patients and their families experienced catastrophic total costs due to TB. The median total cost was 9223.37 CNY (1429.98 USD), in which the median direct and indirect costs of TB patients were 10185.00 CNY (1579.07 USD) and 2400.00 CNY (372.09 USD), respectively, and indirect costs contributed to 43% of total costs. The median OOPE and TOOPE costs were 6024.00 CNY (933.95 USD) and 11890.50 CNY (1843.49 USD), respectively. OOPE and TOOPE had common influencing factors including whether the patient's family had four or more members, a history of hospitalization, combination with other types of TB, the number of visits before diagnosis, and co-occurrence with chronic disease. CONCLUSIONS: The OOPE and TOOPE for TB patients and their families in Sichuan Province are still heavy. In the long run, it is necessary to strengthen education and awareness campaigns on TB related knowledge, disseminate basic medical knowledge to the public, improve healthcare-seeking behavior, and enhance the healthcare infrastructure to improve the accuracy of TB diagnosis and reduce the significant OOPE and TOOPE faced by TB patients and their families in Sichuan Province.

Willingness to practice medicine and related influential factors among medical undergraduates during COVID-19: a cross-sectional study.

BACKGROUND: As the medical undergraduates constitute the future workforce in China, their career preferences hold a significant bearing on the quality of healthcare services, particularly in light of the ongoing COVID-19 pandemic. We aim to understand the current state of the willingness to practice medicine among medical undergraduates and to analyze the related influential factors. METHODS: During the COVID-19 epidemic, we conducted a cross-sectional survey via an online platform from February 15, 2022, to May 31, 2022, to collect participants' demographic information, psychology, and factors influencing their career choices. The general self-efficacy scale (GSES) was used to evaluate medical students' perceptions of their self-efficacy. Futhermore, we conducted multivariate logistic regression analyses to explore the influencing factors of medical undergraduates' willingness to pursure a caree in medicine. RESULTS: A total of 2348 valid questionnaires were included, and 1573 (66.99%) were willing to practice medicine for medical undergraduates after graduation. The mean GESE scores in the willingness group (2.87 ± 0.54) were significantly higher than those of the unwillingness group (2.73 ± 0.49). The multiple logistic regression showed that several factors were positively associated with willingness to practice medicine as a career, including students' GSES score (OR = 1.87), current major, household income, personal ideals (OR = 1.97), family support (OR = 1.44), high income (OR = 1.77), and social respect (OR = 2.19). Compared with those who were very afraid of COVID-19, students who did not express any fear towards the COVID-19 pandemic had a higher preference for choosing the medical profession as a career. Conversely, students thinking of high tension in the doctor-patient relationship, heavy workload, and long training were less likely to choose medical work after graduation. CONCLUSIONS: The study highlights a noteworthy prevalence of medical undergraduates who expressed their willingness to pursue medicine as a career post-graduation. Several factors, including but not limited to current major, household income, psychological factors, personal preferences, and career needs or preferences, were significantly associated with this willingness. Moreover, the impact of the COVID-19 pandemic on medical students' career choices cannot be overlooked.

Exploring charge behavior at the terminal surface and charge separation interface of organo-lead perovskite using in situ surface photovoltage spectroscopy.

The differences in charge separation and transfer processes between the 'non-charge-separation' terminal surface and perovskite/FTO 'charge-separation' interface have been studied using comparative lock-in amplifier-based SPV signals. The SPV phase vector model delves deeper into the direction of charge separation and trapping at the perovskite surface/interface.

Photoelectrochemical Application and Charge Transport Dynamics of a Water-Stable Organic-Inorganic Halide (C6H4NH2CuCl2I) Film in Aqueous Solution.

A water-stable thin film composed of C6H4NH2CuCl2I was fabricated using spin-coating precursor solutions that dissolved equimolar amounts of C6H4NH2I and CuCl2 in N,N-dimethylformamide. Photoelectrochemical characteristics show that the C6H4NH2CuCl2I film demonstrated a stable photocurrent (∼1 µA/cm2) in an aqueous solution under white light (11.5 mW/cm2) even after 3000 s, while exhibiting a photon-to-current efficiency of 0.093% under AM1.5 (100 mW/cm2) illumination. However, these values were significantly lower than those of the CH3NH3PbX3 (X = I, Cl) film in solid devices. The electron diffusion length L(e-) (373 nm) and hole diffusion length L(h+) (177 nm) in the C6H4NH2CuCl2I photoelectrode were significantly lower than those of CH3NH3PbX3, limiting the photoelectrochemical and photocatalysis performances. Moreover, L(h+) was shorter than L(e-) in the C6H4NH2CuCl2I photoelectrode, resulting in the hole-collecting efficiency [ηc(h+)] being lower than the electron-collecting efficiency [ηc(e-)]. A CuO interlayer was introduced as a hole transport layer for the C6H4NH2CuCl2I photoelectrode, which improved L(h+) and ηc(h+).

Ultra-Wideband and Wide-Angle Perfect Solar Energy Absorber Based on Titanium and Silicon Dioxide Colloidal Nanoarray Structure.

In this paper, we designed an ultra-wideband solar energy absorber and approved it numerically by the finite-difference time-domain simulation. The designed solar energy absorber can achieve a high absorption of more than 90% of light in a continuous 3.506 µm (0.596 µm-4.102 µm) wavelength range. The basic structure of the absorber is based on silicon dioxide colloidal crystal and Ti. Since the materials have a high melting point, the designed solar energy absorber can work normally under high temperature, and the structure of this solar energy absorber is simpler than most solar energy absorbers fabricated with traditional metal. In the entire wavelength band researched, the average absorption of the colloidal crystal-based solar energy absorber is as high as 94.3%, demonstrating an excellent performance under the incidence light of AM 1.5 solar spectrum. In the meantime, the absorption spectrum of the solar energy absorber is insensitive to the polarization of light. In comparison to other similar structures, our designed solar energy absorber has various advantages, such as its high absorption in a wide spectrum range and that it is low cost and easy to make.

A Narrow Dual-Band Monolayer Unpatterned Graphene-Based Perfect Absorber with Critical Coupling in the Near Infrared.

The combination of critical coupling and coupled mode theory in this study elevated the absorption performance of a graphene-based absorber in the near-infrared band, achieving perfect absorption in the double bands (98.96% and 98.22%), owing to the guided mode resonance (the coupling of the leak mode and guided mode under the condition of phase matching, which revealed 100% transmission or reflection efficiency in the wavelet band), and a third high-efficiency absorption (91.34%) emerged. During the evaluation of the single-structure, cross-circle-shaped absorber via simulation and theoretical analysis, the cross-circle shaped absorber assumed a conspicuous preponderance through exploring the correlation between absorption and tunable parameters (period, geometric measure, and incident angle of the cross-circle absorber), and by briefly analyzing the quality factors and universal applicability. Hence, the cross-circle resonance structure provides novel potential for the design of a dual-band unpatterned graphene perfect absorber in the near-infrared band, and possesses practical application significance in photoelectric detectors, modulators, optical switching, and numerous other photoelectric devices.

Sb2S3 Thickness-Related Photocurrent and Optoelectronic Processes in TiO2/Sb2S3/P3HT Planar Hybrid Solar Cells.

In this work, a comprehensive understanding of the relationship of photon absorption, internal electrical field, transport path, and relative kinetics on Sb2S3 photovoltaic performance has been investigated. The n-i-p planar structure for TiO2/Sb2S3/P3HT heterojunction hybrid solar cells was conducted, and the photon-to-electron processes including illumination depth, internal electric field, drift velocity and kinetic energy of charges, photo-generated electrons and hole concentration-related surface potential in Sb2S3, charge transport time, and interfacial charge recombination lifetime were studied to reveal the key factors that governed the device photocurrent. Dark J-V curves, Kelvin probe force microscope, and intensity-modulated photocurrent/photovoltage dynamics indicate that internal electric field is the main factors that affect the photocurrent when the Sb2S3 thickness is less than the hole diffusion length. However, when the Sb2S3 thickness is larger than the hole diffusion length, the inferior area in Sb2S3 for holes that cannot be diffused to P3HT would become a dominant factor affecting the photocurrent. The inferior area in Sb2S3 layer for hole collection could also affect the Voc of the device. The reduced collection of holes in P3HT, when the Sb2S3 thickness is larger than the hole diffusion length, would increase the difference between the quasi-Fermi levels of electrons and holes for a lower Voc.

Bias-Dependent Normal and Inverted J- V Hysteresis in Perovskite Solar Cells.

Perovskite solar cells (PSCs) typically exhibit hysteresis in current density-voltage ( J- V) measurements. The most common type of J- V hysteresis in PSCs is normal hysteresis, in which the performance in the reverse scan is better than that in the forward scan. However, inverted hysteresis also exists, in which the reverse scan performance is worse than in the forward scan; this hysteresis, however, is significantly less well studied. In this work, we show that the hysteresis decreases when the sweep rate is decreased only in cases involving a small bias range, and it does not decrease with a large bias range. Under large forward bias and slowing sweep rate, we observe enhanced normal hysteresis or inverted hysteresis in PSCs. Moreover, the degree of normal and inverted hysteresis can be adjusted by varying the bias. Here, we hypothesize that the tunable hysteresis is derived from the different distribution of ionic defects (VI and VMA) at the electron (hole) transport layer/perovskite interface due to ionic movement in the perovskite layer under the different bias scanning conditions. This conclusion is confirmed using Kelvin probe force microscopy with different bias voltages and scanning rates, which shows surface potential hysteresis based on ionic-migration-related Fermi level shifting in perovskite films and agrees with the tunable J- V hysteresis hypothesis. Moreover, the increased time response in the milliseconds region in open-circuit voltage decay after J- V scanning further corroborates the mechanism of ionic migration under bias. Our work provides new insights into the ionic movement hypothesis for the J- V hysteresis in PSCs.

Solution-processed all-oxide bulk heterojunction solar cells based on CuO nanaorod array and TiO2 nanocrystals.

We present a method to synthesize CuO nanorod array/TiO2 nanocrystals bulk heterojunction (BHJ) on fluorine-tin-oxide (FTO) glass, in which single-crystalline p-type semiconductor of the CuO nanorod array is grown on the FTO glass by hydrothermal reaction and the n-type semiconductor of the TiO2 precursor is filled into the CuO nanorods to form well-organized nano-interpenetrating BHJ after air annealing. The interface charge transfer in CuO nanorod array/TiO2 heterojunction is studied by Kelvin probe force microscopy (KPFM). KPFM results demonstrate that the CuO nanorod array/TiO2 heterojunction can realize the transfer of photo-generated electrons from the CuO nanorod array to TiO2. In this work, a solar cell with the structure FTO/CuO nanoarray/TiO2/Al is successfully fabricated, which exhibits an open-circuit voltage (V oc) of 0.20 V and short-circuit current density (J sc) of 0.026 mA cm-2 under AM 1.5 illumination. KPFM studies indicate that the very low performance is caused by an undesirable interface charge transfer. The interfacial surface potential (SP) shows that the electron concentration in the CuO nanorod array changes considerably after illumination due to increased photo-generated electrons, but the change in the electron concentration in TiO2 is much less than in CuO, which indicates that the injection efficiency of the photo-generated electrons from CuO to TiO2 is not satisfactory, resulting in an undesirable J sc in the solar cell. The interface photovoltage from the KPFM measurement shows that the low V oc results from the small interfacial SP difference between CuO and TiO2 because the low injected electron concentration cannot raise the Fermi level significantly in TiO2. This conclusion agrees with the measured work function results under illumination. Hence, improvement of the interfacial electron injection is primary for the CuO nanorod array/TiO2 heterojunction solar cells.